Prepare for a fantasy baseball overreaction -- good or bad -- afterward. That happens when a two-time Cy Young Award winner starts for the first time since 2010 and it's on opening day.

Before breaking down Santana's potential fantasy value, a rewind of his medical history is necessary.

In 2009, Santana was lost after 25 starts because of bone chips in his left elbow. He missed the end of 2010 and all of 2011 because of left shoulder surgery. Santana fell to the 20th round in the Fantasy Source Experts' Draft this year.

Those injury concerns overshadow Santana's line since coming to New York in 2008. From '08-10, Santana went 40-25 with a 2.85 ERA and 496 strikeouts in 600 innings. It's not quite the Cy Young-caliber numbers from his days with Minnesota, but it's also not 20th-round fantasy material. Provided Santana answers those health questions, he's a mid-rotation starter in mixed leagues.

Justin Morneau, 1B/DH, Twins. Morneau, a former teammate of Santana's, also is a high-risk pick. Morneau increased his profile by hitting three homers in a five-game stretch this spring. Over the last two seasons, a severe concussion and wrist injury have limited Morneau to 150 games. However, he still hit .289 with 22 home runs and 86 RBIs in that span. If Morneau can produce that line in one season and avoid health setbacks, he'll be the steal of a standard-league draft.

FALLING

Josh Collmenter, SP, Diamondbacks. In 2011, Collmenter registered a 3.38 ERA and 1.07 WHIP and helped Arizona reach the postseason. Success has not carried over. Collmenter is 0-4 with an 11.81 ERA this spring, and he has surrendered 27 hits in 16 innings. Collmenter already owns a low K/9 rate (5.8), and he had an ERA of 4.50 or more against the Giants, Padres and Dodgers last season. He's not the kind of pitcher who can afford a slow start in standard leagues.

SLEEPER

Mark Melancon, RP, Red Sox. With Andrew Bailey (thumb) likely to be sidelined to start the season, Melancon will battle Alfredo Aceves for closer duties in Boston. Melancon is the better bet to get the job. He had 20 saves with Houston in '11, and that came with a serviceable ERA (2.78) and WHIP (1.22). Boston has averaged 10 save opportunities in March/April the past three seasons. If Melancon takes advantage of the opportunities, he'll be a sneaky-good second closer until Bailey returns.

PROSPECT

Mike Trout, OF, Angels. This highly regarded prospect will start the season at Class AAA Salt Lake, partly because he didn't get much work in spring training because of a shoulder injury and a bout with the flu. Trout wouldn't have logged many at-bats anyway because of the Angels' crowded outfield, but he'll be called up quickly if one of their veterans gets injured. Leave Trout on the waiver wire for now, but closely track his minor league progress.